"The region will be making no further comment and would ask that the media respect Matthew's privacy at this time."

Rees led the Blues in their stirring Heineken Cup victory over reigning European champions Toulon three days ago.

And he would have been expected to be named in the Wales squad for next month's Tests against South Africa, Argentina, Tonga and Australia, which is being announced on Tuesday.

Rees replaced an injured Ryan Jones as Wales captain against Australia in November 2010, and he skippered his country during the Six Nations Championship later that season.

He missed the 2001 World Cup in New Zealand, though, due to a neck injury and his current Blues colleague Sam Warburton took over as national captain.

Although Richard Hibbard is the current first-choice Wales hooker, Rees had remained an important part of the squad under head coach Warren Gatland.

Rees began his career with Welsh club side Pontypridd before joining the Celtic Warriors until they were dissolved. He then went on to make more than 170 appearances for the Scarlets and linked up with the Blues earlier this year.